The Biology of Acupuncture and the Science of China

by Douglas Allchin

Imagine yourself as an American physician visiting a Beijing hospital in 1971. A traditional Chinese doctor there tells you that they can alleviate pain by inserting needles at specific points in the skin and then twirling them slowly. The points are sometimes quite remote from the source of pain. Should you believe them?

Next, you witness a surgery where the main source of pain control is from a needle inserted in the patient's forearm. During the operation, the surgeon makes a 14-inch incision around the left side of the thorax, cuts two ribs, and removes a lobe of a tuberculosis-infected lung. Meanwhile, the patient -- still conscious -- chats with the surgeon. At the end of the 2-hour procedure, the patient sits up and leaves the operating table under his own power, brandishing a copy of Mao's "little red book." Is seeing believing? What, in fact, did you see?

Finally, the doctor, who knows some Western medicine, explains that it is all quite reasonable if you understand traditional Chinese medicine. The needling, the doctor explains, redirects the flow of the life force through the body, balancing the potentially painful influence of the incision. Does the explanation affect the status of your belief? How? Why?

The use of needling as a form of medicine -- a practice known as acupuncture -- extends back for over 2000 years in China. Acupuncture only received widespread exposure in the U.S., however, in the early 1970s when President Nixon began to reestablish U.S. diplomatic ties with the People's Republic of China. American physicians were at first largely baffled by how acupuncture could suppress pain. It followed no known physiological mechanisms. Indeed, it seemed contrary to common-sense notions about pain and the body in general. How could sharp needles alleviate rather than create pain? The Chinese explanation was incredible, but there was no satisfactory Western alternative. What would have been an appropriate 'scientific' response in 1971?

This case poses penetrating questions for students, introducing them to the problems of science in two cultures. In the past few decades Western physiologists have been able to interpret acupuncture's startling analgesic effects in their own terms. And in the fall of 1997 a National Institutes of Health consensus panel finally gave warrant to the efficacy of acupuncutre in several treatments. But some elements of acupuncture still remain explained only in the traditional Chinese system. By introducing the contrasting explanations and research practice, east and west, teachers can raise questions for students about the cultural contexts of science. Cultural symmetry -- the ability to invert cultural perspectives -- is central to making any such case study more effective.

Chinese Tradition and Western Skepticism

Given the spectacle of surgery done under acupuncture startled many Western physicians, it is hardly surprising that some American doctors doubted the Chinese claims. For them, acupuncture was unscientific. They alleged fraud, suggesting that the "demonstrations" for Western physicians had been staged merely to promote China's communist regime. When U.S. doctors began to replicate the effects of acupuncture in American hospitals, however, they had to reconsider. This case allows the teacher to introduce fundamental questions about how scientists judge the credibility of claims, especially indirectly through the credibility of other researchers. Western physicians were clearly accorded more authority than Chinese physicians. Why? In what ways were their judgments justified or unjustified? How would a Chinese physician -- credible among Chinese peers -- have established credibility in a community of Western scientists?

Many people acknowledged the positive effects for persons treated with acupuncture, but they were nonetheless unimpressed for two reasons. First, in about one-third of all cases, a patient recovers from his or her condition even without treatment. For these cases, they argued, it would be inappropriate to credit acupuncture. The historical context of skepticism, here, provides an opportunity to underscore the role of controlled experiments. In other words, students might recognize that to assess the effect of the needling alone, you would need to compare patients treated with acupuncture with those who received no treatment.

From a traditional Chinese perspective, however, the mere idea of such an experiment posed an ethical problem: why would you refrain from a treatment that your experience showed was effective? Chinese medicine stresses the result for the patient. Research is secondary. Therefore, you would not withhold a treatment just for the sake of a test. For the traditional Chinese, if you already knew how to help a patient recover, you did not also need to know why the procedure worked, especially if your research would likely cost patients their well-being. While a Chinese scientist might not disagree with the reasoning behind the design of the controlled experiment, it would be outside proper science. What is the boundary of science and can it vary culturally?

A second reason for disregarding acupuncture, according to some critics, was that pain might be suppressed merely through psychological suggestion -- not a method worthy of serious medical attention. In other words, pain control might have resulted from some "unscientific" influence, such as hypnosis. In 1972 one doctor asserted, "the 'needlism' merely acts as a reinforcing stimulus as well as a diversionary maneuver to disguise the presence of a subtle placebo effect." There was, he claimed, "a misdirection of attention."

Many Westerners were suspicious when they discovered that the Chinese tended to screen patients: not all were deemed eligible for acupuncture. Indeed, the Chinese had considered the attitude of the patient towards acupuncture as early as the Han period (2nd century B.C.). At the same time, Chinese doctors did not distinguish so sharply between psychological and physiological mechanisms. The treatment itself was effective. A Chinese doctor might have replied: is psychosomatic healing not healing? Chinese and Western standards for "good" medicine and science emphasized different values in this instance.

Of course, one could test for the effect of suggestion--and a teacher can invite students to design such a test. They might imagine, for example, that you could check acupuncture on a person or organism that can feel pain but that is not susceptible to suggestion. Both infants and animals, in fact, respond to acupuncture. Acupuncture charts for horses, pigs, water buffalo, camels and other animals dating back to the Yuan period (14th century--before the European Renaissance) offer striking images of the Chinese tradition. Students might be able to interview local veterinarians who now use acupuncture.

Another approach to testing suggestibility, commonly used in drug trials, is to prevent the patient from knowing whether he or she is receiving treatment. Some researchers have used "sham acupuncture," needling at non-acupuncture points. Others have used "treatments" of needles taped to the skin. Students may interpret the results themselves (reviewed in Pomeranz 1987). For acute pain stimuli (such as intense heat or sharp objects) in humans, mice, cats, horses, rats and rabbits, needling of true points clearly suppressed pain, while needling of sham points produced very weak effects. (These responses were studied in the lab, where withdrawal from a painful stimulus could be easily observed and measured.) For the case of chronic (long-lasting) pain, such as backaches or arthritis, results were more complex. Effectiveness was measured clinically by patients' reports of chronic pain relief:

Effectiveness*

sham acupuncture

33%-50%

placebos of needles taped to skin

30%-35%

"true" acupuncture

55%-85%

morphine

70%

(Morphine has been accepted in the West as the most widely effective pain-killer. It serves as a comparison.) (*The differences between groups are statistically significant.)

Why, indeed, were there differences between acute and chronic pain?

Philosophers and sociologists have viewed 'organized skepticism' as a hallmark of (Western) science for some time). This case allows one to assess the role of such skepticism. What may have motivated such strong criticism and concerns about fraud in this case? Given the 2000-year tradition of practice in China, were additional tests warranted? In what ways, if any, did the early criticisms contribute to developing scientific knowledge? Students may consider how incentives or institutionalized checks and balances can either encourage or suppress such motivations. Teachers may invite them to devise a system that might positively regulate their effect.

Physiological Explanations

While some American medical researchers regarded acupuncture as so much hocus-pocus, others were curious to know how acupuncture might work. But the Chinese explanations were based on a fundamentally different, even incompatible "geography" of the body. For the Chinese, the body is maintained by a life force, qi (pronounced as a short, breathy 'chee'). The qi flows through the body along several intersecting meridians or channels. There are twelve primary meridians, each corresponding to a major organ (liver, stomach, spleen, gall bladder, etc.). They also corresponded to the twelve yearly cycles of the moon. The flow of qi along the meridians maintains a balance between yin and yang, the two complementary forces of the universe according to Chinese philosophy. Thus, some meridians or channels are yin, others yang.

The flow of qi along the meridians is how the Chinese traditionally explain health and illness. When the flow is impeded or imbalanced, disease, malfunction or pain results. To restore the balance, needles are inserted at points along the appropriate meridian. The needles either promote or impede the flow of qi, reestablishing the balance of yin and yang.

The concepts of qi and meridians are problematic from a Western perspective because no anatomical structures define the meridians, and no measurable force can be identified as qi. A Westerner may thus be inclined to think that the notions of meridians and qi are superfluous -- perhaps relics of an ancient and discredited cosmology. But the concepts are essential from the perspective of actual practice. Acupuncturists use meridian maps to assess where needles should be placed. Indeed, part of the acupuncturist's skill is diagnosing which meridians have been affected and where along those meridians needles should be placed.

If the notions of qi and meridians have been unsatisfactory for Westerners, numerous studies over the past few decades have given them a more complete understanding in their own terms. Researchers found relatively quickly, for instance, that acupuncture for acute pain stimulates one particular kind of nerve. Most painful stimuli are carried along small fibers. Acupuncture, though, apparently stimulates larger fibers (type II and III muscle afferents).

Other researchers, meanwhile, noticed that the optimal effects of acupuncture often occur after several minutes -- too slowly to be explained by nerve impulses. They wondered if here might be some factor in the blood. Again, students have the opportunity to propose or design possible experiments. In this case, researchers cross-linked the circulation of two rabbits through the veins in their legs. The acupuncture on one rabbit allowed the other to withstand stronger painful stimuli. Cross-injections of cerebral-spinal fluid also worked. They concluded that acupuncture triggered the release of an unknown hormone or similar "messenger" substance.

In 1973, researchers discovered accidentally that the brain releases a class of natural pain- relieving compounds similar to well-known opiate drugs, such as morphine. Among them was endorphin. Was endorphin involved in acupuncture, they wondered. They could study endorphin's possible effects using naloxone, a chemical that inhibited the action of opiates by blocking their receptors on the cell surface. A 1976 study addressed the effects of naloxone injected just prior to acupuncture in rabbits (see Pomeranz 1987, p.9) to see if there was pain relief:

Treatment

Pain Relief?

acupuncture

Yes

acupuncture + naloxone

No

acupuncture + saline

Yes

naloxone (no acupuncture)

No

saline (no acupuncture)

No

acupuncture at non-points (sham acupuncture)

No

handling & restraint (no acupuncture)

No

Again, students may interpret and discuss the results themselves, noting the role of each treatment in reaching their conclusions. How did the controlled experiment contribute to Western understanding here?

Research on pain and acupuncture is far from complete, but the picture is becoming clearer. The system of interactions appears to be quite complex. Numerous nerves originating in the brain and ending at more peripheral points appear to inhibit the transmission of impulses towards the brain. Acupuncture activates many of these inhibitory systems at several levels. In quite different studies, acupuncture has also been linked to increased levels of cortisone, a steroid hormone released from the adrenal cortex. This suggests a link to immune responses. If confirmed, these might help explain acupuncture's other reported health effects in Western terms.

Getting to the Point

The notion that an apparently painful stimulus might reduce pain was paradoxical enough for Americans. But even more puzzling for Westerners were the patterns of needling. Chinese doctors do not insert acupuncture needles haphazardly. There are specific points. Sometimes, the points are quite remote from the site of their intended effect. Thus, you might insert a needle between the thumb and forefinger (a well-known point called ho-ku) to treat either a headache or abdominal cramps(!). For coughing or a fever, you would use a point above the third toe. For Westerners, at least, the correlations made no anatomical sense.

The Chinese explanation for acupuncture, however, accounted for why the points and their effects could sometimes be so distant from each other. Because qi flows along meridians, needles inserted along one meridian may be effective anywhere along that meridian, even though they may be far from the place of the effect. Thus a needle at ho-ku can affect a headache or abdominal cramps because all lie on the 'large intestine' meridian.

Acupuncturists also use the notion of qi in inserting the needle. When needles are placed in the correct location, the patient usually feels a slight distension or numbness. The sensation is called de qi, or "striking the qi," reflecting the view that the patient perceives how the flow of qi changes. Patients can sometimes also feel the numbness of de qi spread along the line of the meridian. Thus, even if the meridians and points have no Western anatomical "reality," they do have a basis in sense perception. And these perceptions guide treatment. For the practicing acupuncturist and the patient, at least, the traditional theory explains key observations. Historically, acupuncturists learned exactly where the points were and how they were connected along meridians by experience. No one could predict, apparently, the sometimes zig- zagging pathways of the meridians--and there is no reason in the Chinese view why they follow the paths as now described. Instead, the meridian maps represent the collected wisdom of generations of acupuncturists.

Westerners could not explain the relationship of points in acupuncture. Not that they hadn't noticed similar phenomena. They were familiar, for example, with 'referred pain'. In these cases, pain from an injured internal organ was felt on the surface of the body, but not always near the organ. Perceptions generally occurred within segments of the body, however. They did not always match the sometimes distant separation of acupuncture points and their effects.

Westerners were also familiar with another set of points, discovered at the end of last century, that evoke pain when pressure is applied. These are now known as 'trigger points'. One physician claimed that sometimes pressure on these points can also alleviate pain. Researchers found in the 1970s that there is a strong correlation between the location of the trigger points of the West and the acupuncture points of traditional Chinese medicine (Melzack et al 1977; Baldry 1993). But again, no one understands fully why trigger points produce pain, sometimes at specific locations remote from the point. In neither case--for trigger points or referred pain--is there an explanation in Western terms why these points might be related to pain relief.

The cross-cultural dimensions of acupuncture can be highlighted once again by new discoveries. In recent years, many points have been found that do not lie on traditional meridians. How would a Western skeptic likely interpret this fact? How might a Chinese doctor interpret the same fact? What can the pair of interpretations reveal about the cultural context of science?

Discovery and Pursuit of Research

What is especially striking is that while Westerners tend to dismiss Chinese explanations, they nevertheless acknowledge that the Chinese discovered acupuncture. Chinese physicians, beginning centuries ago, developed a thorough knowledge of a complex phenomenon that escaped the notice of Western inquiry in the three centuries since the Scientific Revolution. Growth of knowledge is another feature sometimes used to characterize science. In this view, discovery is as central to science as forms of justification. Novel findings, however, do not always emerge from laboratory studies or controlled experiments, another archetypal image of science. To the extent that discovery of new phenomena is a part of science, science in the Chinese culture on this occasion was somehow effective where science in the Western tradition was not.

Science is a process and the pursuit of research can be as significant as its results. Scientists cannot pursue every question, and so they make choices. In addition, their research involves equipment, human effort and time. They must decide where they will invest their limited resources. As noted above, for example, research on acupuncture and its clinical efficacy reflected a degree of commitment, even if based on skepticism. Ultimately, the factors that can influence what research is done help shape science itself. But which research is pursued, and why?

Chinese and American cultures offer very different contexts for the pursuit of research on acupuncture. Acupuncture is valued in China partly in an economic context. It is a relatively "low- tech" form of medicine. It requires little equipment, though it does require expertise and substantial training for the acupuncturist. It is a labor-intensive rather than capital-intensive form of medicine. It was through a deliberate program of research in the late 1950s, in fact, that the Chinese first applied and then developed acupuncture as a form of analgesia for dental work and, subsequently, surgery.

The circumstances for acupuncture research in highly industrialized, capitalist nations are quite different. Because acupuncture involves no product to sell, drug companies and other investors have had little incentive to fund acupuncture research. There is no opportunity for profit. By contrast, research on endorphin-like molecules that may relieve pain has been well funded. Funds exist for research on pain relief, but only for certain types of pain relief. The prospect for knowing more about acupuncture thus depends on certain sources of funding to support research--in this case, support for 'basic' research.

In addition, acupuncture in the U.S. is still widely viewed as an "alternative" or "folk" medicine. It has peripheral status. Many insurance companies or health plans, for example, do not pay for acupuncture treatments. Even Western doctors sympathetic to acupuncture often recommend it only when Western medicine fails or is first shown to be ineffective. Many practitioners and health administrators say that scientific assessments leave the efficacy and explanations of acupuncture still uncertain. They also continue to cite the potential for fraud (see, e.g., Consumer Reports, 1994). With the current commitments to Western medicine, the potential of acupuncture--and hence research on it--will be limited. What we know about acupuncture will be shaped, as it has in the past, by the research that is done.

Cross-Cultural Perspectives and Cultural Symmetry

The case of acupuncture effectively illustrates how to appreciate the cultural context of science, I think, because one can compare--and perhaps feel the tension between--two different cultural perspectives. First, it is possible to understand and to appreciate independently the perspective of each culture. In this case--as perhaps in most cases of cultural divergence in science-- the contrast is especially dramatic because one must undergo a gestalt-like conceptual shift when moving from one way of thinking to the other.

Second, neither account conveniently reduces to the other. The Western accounts of nerve pathways and the effects of endorphin offer powerful ways to relate acupuncture to other aspects of pain and physiology in general where traditional Chinese explanations remain silent. At the same time, the Chinese lay claim to the original discovery and to explanations on the sensations of de qi and clinical practice. Neither culture has "cornered the market" on explanations for acupuncture. The standards for scientific practice in each culture relate to what each knows. I suggest that such tensions offer the cognitive dissonance or discrepant episodes that effectively prompt students to reflect on the cultural contexts of science.

A basic test for a cultural case study, then, is whether it works symmetrically. That is, the example should be equally effective from each cultural perspective, or if the cultural perspective is reversed.

References

'Acupuncture', Consumer Reports 59 (Jan., 1994): 54-59.

Lu and J. Needham. Celestial Lancets: A History of Acupuncture and Moxibustion. Cambridge University Press.

NIH consensus panel opinion, an institutionalized symbol of Western medicine, gave acupuncture a landmark thumbs-up rating in fall, 1997. This document draws on evidence that was mostly available over ten years ago -- hence there is occasion for discussion of the timing of the decision.

Any search engine will deliver a list of sites: can students sort the scientifically reliable information at some sites from the questionable claims at commercial sites and those of various "enthusiasts"? How does one assess this?

The SHiPS Teachers' Network helps teachers share experiences and resources for integrating history, philosophy and sociology of science in the the science classroom.